Hey brain,
As of now, scanning words will do just fine. When you find a word or group of words relevent to your purpose, dip in. When you think to yourself "this section is interesting to me," dip in. Those are the clues you should look for at first. When you do this more and more,you will eventually be able to just know which parts of the book the information you are looking for is in.
And for your next question, yes, I am able to do that.
For example.
For one of my classes in school, a certain fossil had been mentioned. I couldn't remember the name, and so there was a book sitting around my house about fossils. What did I do? I photoread, turned to a page (spontaneously) and the first word I looked at was exactly what I was looking for. That was yet another experience that truly told me, something is definitely going on during the photoreading step.
I hadn't consciously noticed it while photoreading, so that told me this was a legitimate experience.
-JackTuff13